TIMBER ESTIMATING. 59 



of purchase, and the seller wishes to obtain an adequate return 

 for his material. In case of an ordinary lumbering operation where 

 all merchantable material is taken, the quantity of wood products 

 actually cut, as indicated by the log scale, or by measurement on 

 the ground of the logs produced, gives a comparison by which the 

 accuracy of an estimate of standing timber may be judged. 



The first products of the forest are: Logs intended for lumber, 

 poles, ties, or posts, and cord wood. With few exceptions the tim- 

 ber is converted into the product which has the greatest stumpage 

 value or readiest sale, and it should be estimated in terms of this 

 product usually saw logs. 



The contents of logs are measured by log rules. No two of the 

 many log rules now in use give equal volumes for logs of identical 

 dimensions, and the extreme variation in the scale of a given lot 

 of logs by different rules may be greater than 20 per cent. And 

 even by the same rule, logs may be scaled closely or very loosely; 

 liberal allowance may be made for defects or practically no allow- 

 ance at all, according to the training of the sealer or the closeness 

 of utilization. 



The closeness with which the timber is utilized will vary in a 

 given stand. As stumpage values increase, the aim will always be 

 to secure more timber by cutting to smaller diameter, by lower 

 stumps, and by utilizing up to a smaller diameter at the top. 

 Species which were at first considered unmerchantable and later 

 become valuable must be estimated. Improved transportation 

 facilities and the introduction of better logging machinery encour- 

 age the removal of poorer classes of logs formerly unprofitable. 

 For these reasons estimates have to be revised to correspond with 

 advance in values, and old estimates, even if they were correct 

 when made, are usually too small for present market conditions. 



Since there are so many and so various factors influencing the 

 standard of measurement, it is seldom possible to make an estimate 

 of timber which will come closer than within 10 per cent of the 

 actual quantity standing on the ground. Yet an estimate must 

 always' be based on the present market conditions, except when 

 the owner plans to hold his timber for an expected improvement in 

 values, and therefore requires an estimate which will include 

 species and sizes not now merchantable. 



